Fix SseIntegratioTest

[devcrocod]

• use dynamic port

Motivation and Context

How Has This Been Tested?

Breaking Changes

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

Additional context

[tiginamaria]

lgtm! Am I right that the issue was that the static port can sometimes be in use on macOS or in CI environments, so assigning a dynamic port in tests is just safer?

[devcrocod]

@tiginamaria
yes, back when there were fewer targets, server had enough time to be released